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@#Objective 聽 聽To evaluate the mid-term outcomes between tricuspid valve detachment (TVD) and non-detachment (NTVD) for ventricular septal defect (VSD). Methods 聽 聽 The patients who underwent perimembranous VSD repair in the Department of Cardiovascular Surgery, West China Hospital from 2015 to 2020 were included. According to the surgical method, the patients were divided into a TVD group and a NTVD group. The clinical data of the two groups were compared. Results 聽 聽 Totally 538 patients were included in the study. There were 240 patients in the TVD group, including 121 males and 119 females, with an average age of 3.85卤8.42 years and an average weight of 14.12卤12.97 kg. There were 298 patients in the NTVD group, including 149 males and 149 females, with an average age of 4.42卤9.36 years and an average weight of 14.87卤12.51 kg. There was no statistical difference in the age, weight, sex, preoperative New York Heart Association (NYHA) classification or tricuspid regurgitation (TR) degree between the two groups (P>0.05). Median follow-up was 30 (23, 40) months in the TVD group, and 29 (23, 41) months in the NTVD group (P=0.600). After operation, one patient in each group developed third-degree atrioventricular block and recovered to sinus rhythm before discharge (P=0.848). No pacemaker was needed. There was no statistical difference in the length of stay (P=0.054), mortality (P=1.000), in-hospital reoperation (P=0.199), or follow-up reoperation (P=0.505). More than 98% of patients in both groups had postoperative TR less than moderate (P=0.926). At the last follow-up, only 7 (2.9%) patients in the TVD group were detected trivial residual shunting, and 14 (4.7%) in the NTVD group (P=0.289). No one needed to have reoperation because of residual VSD. The TVD group showed less TR during the follow-up (P=0.019). Conclusion TVD is an alternative technique which can be safely used in the closure of VSD, especially in technologically mature medical center. Appropriate tricuspid valve detachment for those hard-to-expose VSDs does not result in poorer tricuspid valve function or higher risk of atrioventricular block, and might reduce the incidence of residual shunting.
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BACKGROUND:Many studies reported the relationship of the mechanical properties and water content about bone tissue, which is one of organizations containing the lowest water content on human body. Researches on effect of water on biological tribology behavior of bone tissue have been rarely reported and are the experimental study generally. OBJECTIVE:To explore the influence and the damage mechanism of water on biological tribology behavior of bone tissue, by comparing multiscale numerical model established with the experiment. METHODS:Dehydration of the bone tissue was studied by nanoindentation test and both reciprocating sliding and impact wear tests. A multi-scale finite element model was constructed under a flat-on-ball configuration. RESULTS AND CONCLUSION:The viscoelasticity and the tribological properties of bone tissue significantly decreased as well as the different wear mechanisms under applied loading after drying. The analytical results indicated that there were high stress condition, which incurred the micro-crack initiation and the appearance of peeling and wear, around the Haversian canal, circumferential lamellas and the interstitial tissues. Meso-scale:dehydration weakened the function of absorption and interruption of stress, which facilitated crack extension in pore. Micro-scale:the high stress gradient of structure of canaliculi and lacunae is an important cause of tissue damage.